Slide fastener



B. C. ROEHRL SLIDE FASTENER Jan. 8, 1952 2 SHEETS-SHEET 1 Filed April1'7, 1946 Patented Jan. 8, 1952 SLIDE FASTENER Bruno C. Roehrl, Erie,Pa.,

assignor to National Organ Supply Company, Erie, Pa., a corporation ofPennsylvania Application April 17, 1946, Serial No. 662,706

4 Claims. 1

This invention is intended to provide a slide fastener having matingstrips of flexible plastic, such as polyethylene, vinylite, etc. havecontinuous locking shoulders which cannot be jammed by threads and whichmake a dust tight seal. Because all of the surfaces of the fastener aresmooth, it is easy to keep clean. Further objects and advantages appearin the specification and claims.

In the drawings, Fig. 1 is a top view of the fastener; Figs. 2 to 6 aresections on correspondingly numbered lines in Fig. 1; Fig. 7 is a topview of the slide; Fig. 8 is a section on line 8--8 of the slide; andFig. 9 is an end view of the slide.

Referring to the drawing, I and 2 indicate the mating strips comprisingthe slide fastener. These strips may be extruded from flexiblethermoplastics of the class known as elastomers, such as polyethylene,or vinylite. These materials are particularly adapted to this fastenersince they are substantially non-stretchable, non-corrosive,

have a low coeflicient of friction, and come in a wide variety ofcolors.

At the outer edge of each of the strips is a tongue 3 to which isfastened a tape 4 by which the strips can be sewn as in the conventionalslide fastener. The edges 5 of the tape are folded over the upper andlower surfaces of the tongue, being located by shoulders 6 and fastenedto the tongue either by an adhesive or by pressing the tape against thetongue while it is heated above the Softening temperature. The strip Iis extruded in a single piece. The strip 2 is extruded in upper andlower halves which are cemented together along a surface I at the outeredge, leaving the inner ends 8 and 9 free to flex transversely to thestrip.

In the closed position of the fastener. the inner end III of the strip Iis received between the inner ends 8 and 9 of the strip 2. On the outerface of the inner edge of the strip I is a rib or bead II having anundercut locking shoulder I 2 which cooperates with an undercut lockingshoulder I3 on a rib or bead It at the inner edge of the end 8 of thestrip 2. Because the looking shoulders I2 and I3 are continuous andundercut, the shoulders form a substantially airtight seal andeffectively resist separation of the fastener even though the ribs IIand I4 may flex slightly. on the under side of the inner edge of thestrip I' is a rounded rib or bead I5 which in the closed position of thefastener cooperates with a rib or bead IS on the inner edge of the end 8of the strip 2 and identical with the rib I4. The ribs I5 and I6 are notintended to lock the fas- The stri psedges of the strips.

2 tener in the closed position, but merely to locate the inner edges ofthe fastener.

On the outer surface of the fastener is a slide ll which bridges thejoint between the inner The outer ends of the slide have dove-tailgrooves II which slide on dovetail ribs I9 on the outer surface'of therespective strips. As indicated in Fig. 1, the grooves I8 are curvedalong the length of the slide. At the line 6-6 in Fig. 1, the spacing ofthe grooves is equal to the normal separation of the ribs I9 in theclosed position of the fastener. At the line 5-5 in Fig. 1. the grooves[8 are closer together than in the line 6--6, thereby forcing the stripsedgewise toward each other so that the undercut locking shoulders I2 andI3 are clear. In this position the fastener can be unlocked by lifting'the end I of the strip 2. This lifting is accomplished by an inclinedwedge or cam 20 which rides on the outer face of the strip I andcooperates with the surface 2I on the under side of the rib I I. At thehighest point of the wedge 20, the inner end 8 of the strip 2 is liftedto the position shown in Fig. 4. In Fig. 4 the strip 2 has been startedto move edgewise away from the strip I by contact with the taperedsection 22 on the inner wall of the slide. The tapered section 22reaches its maximum thickness shortly before the line 2-2 in Fig. 1, atwhich point the locking shoulders of the fastener are completelyseparated, as indicated in Fig. 2. The separating or unlocking movementof the strips is slightly resisted by the rounded rib I5 on the underside of the strip I. but the resistance offered is lnsumcient tointerfere with the operation of the slide. The locking and unlocking ofthe fastener do not injure or stress the locking surfaces I2 and I3since these surfaces are out of contact during both the locking andunlocking movement of the slide. This prevents rounding of the lockingshoulders which would make the locking of the fastener less secure.

It will be noted that the strips of the fastener are flexed to someextent at all points between the ends of the slide I"I. When thefastener is made of thermo-plastic material which has a ten dency tocold flow or set, there is a possibility that the portion of the stripsbetween the ends of the slide might take a permanent set which wouldinterfere with the operation of the fastener. This is of minorimportance at points intermediate the ends of the fastener since theslide will rarely be left for any appi eciable length of time in aposition corresponding to a partly opened and partly closed position ofthe fastener.

The slide is, however,

likely to be left at the extreme ends of the fastener, at which pointsthe parts of the strip within the slide would be flexed to the positionsillustrated in Figs. 2 to 6. The flexing of the fastener to the positionindicated in Fig. is not serious since the ordinary stresses on thefastener will tend to move the locking shoulders l2 and I3 into contactand thereby overcome any set due to the edgewise curvature of thestrips.

The flexing indicated in Figs. 3 and 4 is more serious since itseparates or spreads the ends 8 and 9 of the strip 2 and therebydecreases the resilience with which the ends grip the inner ends of thestrip I. This flexing can be eliminated by tapering the projectingportions of the ribs 1 I, I4, I5 and Hi to the point indicated by dottedlines 23, 24, 25 and 26. This tapering is gradual so as not to provideany abrupt surfaces which would interfere with the operation of theslide. It can be accomplished by planing the outer surfaces of the ribsat the extreme ends of the fastener.

While 'it is true that the removal of the ribs removes the lockingshoulders, the locking shoulders are not necessary for the part of thefastener between the ends of the slide since the slide through theaction of the dove-tail grooves and ribs 18 and I9 holds the fastenertogether.

In the assembly of the fastener, the strips I and 2 are assembled in theclosed position, and one end of the strips is permanently fastenedeither by an adhesive or by heating to a softening temperature andpressing the ends together. The slide is then slid onto the other end ofthe strips, the dove-tail ribs l9 being received in the dovetail groovesl8. A stop may then be added to the extreme end of one of the strips toprevent removal of the slide.

' shoulder cooperating with the first shoulder and the inner of whichprovides a shoulder in nonlocking cooperating with the second shoulder,ribs on the outer faces of the respective strips having undercut groovesin the outer edges, a slide extending across the outer faces of thestrips with ends received in the grooves, said ends converging to movethe strips edgewise toward each other to move the undercut lockingshoulders clear of each other and then diverging, and a cam on the slidehaving a portion riding on the outer face of the first strip andextending between the outer face of the first strip and the cooperatingside of the mating strip for camming the locking shoulders apart in theportion of the strips where the locking shoulders are clear of eachother.

2. In a slide fastener, a flexible non-stretchable strip having alongone face only a rib defining an undercut locking shoulder, a matingflexible non-stretchable strip having a channel loosely receiving thefirst strip with sides resiliently engaging opposite faces thereof, oneside having an undercut locking shoulder cooperating with the unlocked,and said first cam means having a portion cooperating with the stripsbeyond the point at which the shoulders are unlocked for camming thestrips edgewise apart to separate the strips.

3. In a slide fastener, a flexible non-stretchable strip having on itsouter face only a rib defining an undercut locking shoulder, a matingflexible non-stretchable strip having a channel loosely receiving thefirst strip with sides resiliently engaging opposite faces thereof, theouter side of the channel having an undercut locking shouldercooperating with the first shoulder to prevent edgewise separation ofthe strips, dovetail ribs on the outer faces of the strips, a slidehaving grooves receiving the dovetail ribs, the grooves converging fromthe locked and of the slide to move the strips edgewise until theshoulders are clear and then diverging toward the unlocked end of theslide, and a cam on' the slide acting between the outer face of thefirst strip and the outer channel side to wedge apart the portions ofthe shoulders which are clear.

4. In a slide fastener of strips of flexible nonstretchablethermoplastic of the class known as elastomers and characterized by alow coefllcient of friction, a flexible strip having along its outerface only a rib defining an undercut locking shoulder, a mating flexiblestrip having a channel loosely receiving the first strip with sidesresiliently engaging inner and outer faces thereof, the outer channelside having an undercut looking shoulder cooperating with the firstshoulder to prevent edgewise separation of the strips, a slide foropening and closing the fastener on the outer face of the strips havingends slidably anchored on the respective strips, said ends converging tomove the strips edgewise toward each other to move the undercut lockingshoulders clear of each other and then diverging, and a cam on the slideriding on the outer face of the first strip extending only-between theouter face of the first strip and the outer channel side to cam' theshoulders apart in the portion of the strips where the locking shouldersare ,clear of each other.

BRUNO C. ROEHRL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

